1. Field of the Invention
This invention relates to a silver catalyst for the production of ethylene oxide. More particularly, this invention relates to a silver catalyst which is used in the production of ethylene oxide by the catalytic vapor phase oxidation of ethylene with molecular oxygen.
2. Description of Prior Arts
The catalyst which is used in the production, on a commercial scale, of ethylene oxide by the catalytic vapor phase oxidation of ethylene with molecular oxygen is required to possess high activity, high selectivity and high durability. Various studies have been made to date with a view to improving such properties of the catalyst. In this connection, efforts have been made to improve reaction promoters, carriers and silver compounds. Many reports covering reaction promoters are found in patents. For example, U.S. Pat. No. 3,962,136, U.S. Pat. No. 4,007,135, British Pat. No. 1,489,335, U.S. Pat. No. 4,039,561 disclose inventions relating to reaction promoters. Most of the inventions are directed to improving the properties of the catalyst by addition of alkali metals belonging in a limit confining within.
The existing carrier for the catalyst still leaves much to be clarified and improved. For example, physical properties of the carrier such as specific surface area, pore diameter, pore distribution, pore volume and porosity and chemical properties of such carrier materials as .alpha.-alumina, silicon, carbide, silica and zirconia await improvements for the sake of optimization.
It is, therefore, an object of this invention to provide a novel silver catalyst for the production of ethylene oxide.
Another object of this invention is to provide a silver catalyst of high activity, high selectivity and high durability for use in the production of ethylene oxide.